I have a lot of experience with APR and several of their rifles. Great guys, they do have their in stock rifles that you can look up on their website, but I've also designed several reamers and built them from the ground up. They will do whatever you want.
All of mine have shot .3" groups or less with hand loads, with some shooting in the .1's. 6mm creed up to 300 RUM.
Robert, Jason and the team also compete in ELR competitions and won the King of 2 Mile competition last year. There's a lot of factors that go into shooting that far, but not the least is a super accurate rifle.
They know what they're doing.
Here's a few group pics for fun of my APR rifles at 100 yards and on steel at 750 yards.